Water treatment management device, water treatment management system, and water treatment method

Abstract

To make it possible to properly operate a water treatment system by monitoring and evaluating raw water, when it is probable that various persistent TOC components are contained in raw water supplied to a water treatment system such as an ultrapure water manufacturing system.SOLUTION: A water treatment control device 20 used for operational control of a water treatment system is provided with: a TOC removal device that performs a unit operation to remove TOC components; an evaluation pure water manufacturing section 30 through which raw water to be supplied to a water treatment system is passed as target water; a TOC meter 25 that measures a TOC concentration in the outlet water of at least the evaluation pure water manufacturing section 30; a specific organic component measuring device 23 that measures the specific organic component concentration such as urea in water flowing the evaluation pure water manufacturing section 30; a calculation section 26 executing calculation based on the TOC concentration and measurement results by the specific organic component measuring device; and a flow path control section 27 controlling flow paths 41, 46, 51 that supplies raw water to the water treatment system, based on calculated results at the calculation section 26.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a water treatment management device and a water treatment management system used when performing water treatment such as ultrapure water production by a water treatment system, and a water treatment method. [Background technology]

[0002] Water treatment systems, such as ultrapure water production systems that produce ultrapure water from raw water, must also pay attention to the quality of the raw water supplied to the water treatment system. For example, ultrapure water production systems use reverse osmosis (RO) and ultraviolet (UV) oxidation processes to remove organic substances (TOC, or total organic carbon) from raw water. However, some organic components are easily removed by these processes, while others are not. In the following explanation, TOC components that are difficult to remove using RO and UV oxidation processes, especially those that are difficult to decompose and remove using conventional UV oxidation processes, are referred to as persistent TOC components. For example, urea is known to be difficult to remove using RO and UV oxidation processes and is classified as a persistent TOC component. Other organic substances besides urea are known to be persistent TOC components. If persistent TOC components are mixed into raw water, they may affect the quality of the treated water at the outlet of a water treatment system, such as an ultrapure water production system. Furthermore, even if they are not persistent TOC components, there are organic substances that, when present in raw water, can have a significant impact on the quality of treated water. For example, volatile organic compounds (VOCs) such as toluene and xylene, trihalomethanes such as chloroform and bromoform, tetramethylammonium hydroxide (TMAH), and low-molecular-weight alcohols cannot be completely removed by reverse osmosis membrane treatment or ultraviolet oxidation treatment if they are present in high concentrations in raw water, and this can have an impact on the quality of treated water in water treatment systems.

[0003] Until now, tap water, municipal water, industrial water, and other sources have been used as raw water for ultrapure water production systems. In recent years, in order to efficiently utilize water resources, reclaimed water or recycled water, which is obtained by first treating industrial wastewater or treated sewage, has begun to be used as raw water. Unlike industrial water, the quality of reclaimed water and recycled water may be unstable, and they may suddenly contain unexpected organic matter. In particular, for ultrapure water production systems with high treatment capacities, it takes time for changes in the quality of the raw water supplied to the system to reach the outlet. Therefore, it is not appropriate to respond to changes in the quality of the raw water by detecting changes in the quality of the treated water obtained from the outlet. It is becoming increasingly important to monitor the quality of the raw water in ultrapure water production systems and appropriately manage the operation of the ultrapure water production system according to the water quality.

[0004] Patent Document 1 discloses the provision of a sub-ultrapure water production system for monitoring and controlling the quality of raw water when a main ultrapure water production system is installed to produce ultrapure water to be supplied to a point of use from raw water. The sub-ultrapure water production system has a configuration equivalent to that of the main ultrapure water production system and produces ultrapure water of similar quality. The TOC concentration of the ultrapure water obtained from the sub-ultrapure water production system is measured, the quality of the raw water is evaluated based on the TOC concentration, and the amount of raw water supplied to the main ultrapure water production system is controlled based on the evaluation results. In the system described in Patent Document 1, for example, if the TOC concentration in the ultrapure water obtained from the sub-ultrapure water production system is high, the supply of raw water to the main ultrapure water production system can be stopped, the raw water can be supplied to the main ultrapure water production system via a urea removal device, or the UV irradiation amount can be increased in an ultraviolet irradiation device.

[0005] Patent Document 2 discloses a technology for managing the operation of a water treatment system, such as an ultrapure water production system that supplies ultrapure water to a point of use, in which a pure water production unit for evaluation is provided separately from the water treatment system, the pure water production unit for evaluation being equipped with a TOC removal device that performs a unit operation to remove TOC components, and the TOC concentrations at multiple measurement points in the pure water production unit for evaluation are measured and these TOC concentration values ​​are analyzed to evaluate the target water. The technology described in Patent Document 2 can control the supply of raw water to the water treatment system according to the evaluation results; for example, if the target water, which is raw water, is evaluated to contain persistent TOC components, control can be performed such that the raw water is not supplied to the water treatment system.

[0006] As a technique for continuously measuring the urea concentration in raw water used for producing pure water online, Patent Document 3 discloses that the quantification of urea is carried out by flow injection analysis using a colorimetric method using diacetyl monoxime. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-107249 [Patent Document 2] Japanese Patent Application Publication No. 2019-155275 [Patent Document 3] Japanese Patent Application Publication No. 2018-179545 Summary of the Invention [Problem to be solved by the invention]

[0008] In the system described in Patent Document 1, the persistent TOC component detected in the sub-ultrapure water production system is not necessarily urea. Therefore, when persistent TOC components other than urea are present in the raw water, appropriate treatment cannot be performed, and persistent TOC components remain in the outlet water of the main ultrapure water production system, potentially deteriorating the quality of the resulting ultrapure water. Furthermore, even organic components that are easily removed by reverse osmosis membrane treatment or ultraviolet oxidation treatment may not be completely removed by these treatments if the raw water contains high concentrations of these components, potentially affecting the quality of the treated water. Meanwhile, in the system equipped with the water treatment monitoring device described in Patent Document 2, when the raw water is determined to contain persistent TOC, there is no option other than to limit the amount of raw water supplied to the water treatment system, resulting in a problem of reduced water resource utilization.

[0009] An object of the present invention is to provide a water treatment management device, a water treatment management system, and a water treatment method that can monitor and evaluate raw water and appropriately operate the water treatment system when there is a possibility that the raw water supplied to a water treatment system such as an ultrapure water production system may contain organic components such as various persistent TOC components, the above-mentioned volatile organic substances, trihalomethanes, tetramethylammonium hydroxide, and low-molecular-weight alcohols. [Means for solving the problem]

[0010] The water treatment management device of the present invention is a water treatment management device used for managing the operation of a water treatment system, and is equipped with a TOC removal device that performs a unit operation to remove TOC components, and a pure water production section for evaluation through which raw water to be supplied to the water treatment system is passed as target water, and a TOC concentration control section for controlling at least the TOC concentration in the outlet water of the pure water production section for evaluation. As the first density value TOC measurement equipment and the water flowing through the evaluation pure water production section , which is a concentration different from the TOC concentration The concentration of specific organic components as the second concentration value The system includes a specific organic component measuring device that measures the specific organic component, a calculation unit that performs calculations based on the TOC concentration and the concentration of the specific organic component, and a flow path control unit that controls the flow path that supplies the raw water to the water treatment system based on the results of the calculations in the calculation unit.

[0011] The water treatment management system of the present invention comprises a water treatment management device of the present invention and a pretreatment flow path network having a plurality of flow paths arranged in series with each other in a route supplying raw water to the water treatment system, and the water treatment management device controls the flow paths that supply raw water to the water treatment system by selecting one or more flow paths in the pretreatment flow path network.

[0012] The water treatment method of the present invention is a water treatment method for supplying raw water to a water treatment system, and includes the steps of: passing the raw water as target water through a pure water production section for evaluation, which is provided separately from the water treatment system and has a TOC removal device that performs a unit operation to remove TOC components; and measuring the amount of the target water in at least the outlet water of the pure water production section for evaluation. , which is a concentration different from the TOC concentration TOC concentration As the first density value The first measurement step measures the concentration of specific organic components in the water flowing through the evaluation pure water production unit. as the second concentration value a second measuring step of measuring; 1st concentration value and Second concentration value and a flow path control step of controlling a flow path that supplies raw water to the water treatment system based on the result of the calculation based on the above. [Effects of the Invention]

[0013] According to the present invention, even when the raw water contains various persistent TOC components and other organic components, it is possible to monitor and evaluate the raw water and operate the water treatment system appropriately. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a diagram showing a configuration of a water treatment management system according to a first embodiment of the present invention. [Figure 2] 1 is a flowchart illustrating an example of an operation of the water treatment management system. [Figure 3] FIG. 4 is a diagram showing the configuration of a water treatment management apparatus according to a second embodiment. [Figure 4] FIG. 10 is a diagram showing the configuration of a water treatment management apparatus according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Next, an embodiment of the present invention will be described with reference to the drawings.

[0016] [First embodiment] FIG. 1 shows a water treatment control system according to a first embodiment of the present invention. Given a water treatment system 10, such as an ultrapure water production system for producing ultrapure water from raw water, the water treatment control system according to the present invention supplies raw water to the water treatment system 10 with or without pretreatment depending on the quality of the raw water. The water treatment control system includes a water treatment control device 20 and a pretreatment flow network 40. A raw water tank 11 is provided for temporarily storing raw water to be supplied to the water treatment system 10. The raw water is supplied to the water treatment system 10 by passing from the raw water tank 11 through piping 12, the pretreatment flow network 40, and piping 13, in that order. The water treatment control device 20 is used for operational management of the water treatment system 10. The water treatment control device 20 monitors and evaluates the quality of the raw water stored in the raw water tank 11 as target water and controls the pretreatment flow network 40 based on the evaluation results. In particular, the water treatment control device 20 confirms the presence of persistent TOC components in the target water and monitors their concentrations. Here, persistent TOC components refer to TOC components that are difficult to remove using reverse osmosis membrane treatment or UV oxidation treatment, particularly those that are difficult to decompose and remove using conventional UV oxidation treatment. Urea is also a type of persistent TOC component, but because urea often accounts for the majority of persistent TOC components in raw water, it is more convenient to treat it separately from other persistent TOC components. Furthermore, as mentioned above, there are organic substances that are not persistent TOC components but that, when present in raw water, can affect the quality of treated water. Therefore, the water treatment management device 20 of this embodiment is configured to measure the concentrations of specific organic components in addition to the overall concentration of persistent TOC components. The specific organic components referred to here are one or more organic substances selected from the group consisting of urea, volatile organic substances (e.g., toluene and xylene), trihalomethanes (e.g., chloroform and bromoform), tetramethylammonium hydroxide, and low-molecular-weight alcohols. The raw water may be, for example, industrial water or recycled water, but in the following description, the water to be supplied to the water treatment system 10 will be broadly referred to as raw water. The water treatment system 10 may be configured to be able to switch between supplying raw water from different supply sources.

[0017] The water treatment management system 20 includes a pure water production unit 30 for evaluation, which produces pure water from raw water supplied as target water from a raw water tank 11 for evaluation. The pure water production unit 30 for evaluation is composed of a combination of multiple types of TOC removal equipment that performs a unit operation to remove TOC components. Here, the pure water production unit 30 for evaluation includes a heat exchanger (HE) 31 for adjusting the temperature of the target water, a reverse osmosis membrane device (RO) 32 to which outlet water from the heat exchanger 31 is supplied, an ultraviolet irradiation device (UV) 33 to which permeated water from the reverse osmosis membrane device 32 (RO permeated water) is supplied and which performs ultraviolet oxidation treatment on this water, and an ion exchanger to which outlet water from the UV irradiation device 33 is supplied and which performs ion exchange treatment. The outlet water from the ion exchanger is the outlet water of the pure water production unit 30 for evaluation. This outlet water is pure water. The reverse osmosis membrane device 32 may be a multi-stage device in which permeated water from a previous reverse osmosis membrane is supplied to a subsequent reverse osmosis membrane. There is no particular limitation on the type of reverse osmosis membrane used in the reverse osmosis membrane device 32, but from the viewpoint of, for example, saving energy in the pump, it is preferable to use an ultra-low pressure reverse osmosis membrane or a low pressure reverse osmosis membrane. The reverse osmosis membrane device 32 is preferably operated at a recovery rate of 15 to 50%. There is no particular limitation on the amount of ultraviolet radiation in the ultraviolet radiation device 33, but it is preferably, for example, 0.05 to 3 kWh / m 3The irradiation dose can be adjusted to achieve a value of 1000 ppm. In the illustrated example, a cartridge polisher (CP) 34 (also called a non-regenerative ion exchanger) filled with a mixed bed of anion exchange resin and cation exchange resin is used as the ion exchanger. The outlet water of the evaluation pure water production unit 30 is discharged to the outside via a valve 21. The reverse osmosis membrane device 32, ultraviolet irradiation device 33, and cartridge polisher 34 are all TOC removal devices that perform a unit operation to remove TOC components. Note that pretreatment of the raw water supplied to the water treatment management system 20 may involve passing the water through a cartridge filter or activated carbon, or adding chemicals such as acid or alkali. The water treatment management system 20 may also be equipped with a membrane degasser or an electrodeionization (EDI) device depending on the water quality items to be monitored and their management level. The electrodeionized water production apparatus can be placed, for example, in place of the cartridge polisher 34 to reduce the frequency of replacing the ion exchange resin, or between the reverse osmosis membrane device 32 and the ultraviolet irradiation device 33 to improve the TOC removal efficiency in the ultraviolet irradiation device 33. The water treatment management apparatus 20 does not necessarily need to be provided with the heat exchanger 31.

[0018] Because persistent TOC components are hardly removed by the TOC removal devices in the evaluation pure water production unit 30, persistent TOC components contained in the target water appear in the outlet water of the evaluation pure water production unit 30. Therefore, to evaluate the persistent TOC components contained in the target water, the water treatment management system 20 supplies a portion of the outlet water of the evaluation pure water production unit 30 via valve 24 to a TOC meter 25, a TOC measurement device that measures TOC concentration. Because TOC components that can be easily removed by conventional TOC removal devices are removed before reaching the outlet of the evaluation pure water production unit 30, the TOC concentration measured by the TOC meter 25 can be considered to be the carbon-equivalent concentration of persistent TOC components. Furthermore, to measure the concentration of urea contained in the target water, the water treatment management system 20 branches a portion of the target water supplied to the evaluation pure water production unit 30 and supplies it via valve 22 to a specific organic component measurement device 23. The specific organic component measurement device 23 is a measurement device that measures the concentration of the specific organic components described above in water. When the specific organic component measuring device 23 is configured as a urea meter for measuring the urea concentration in water, the specific organic component measuring device 23 may have a configuration such as that shown in Patent Document 3. Alternatively, the specific organic component measuring device 23 may be a VOC meter for measuring the concentration of volatile organic substances in water, a combination of a urea meter and a VOC meter, a trihalomethane meter for measuring the concentration of trihalomethanes, a TMAH meter for measuring the concentration of tetramethylammonium hydroxide, an alcohol concentration meter for measuring the concentration of alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol, or a combination of these measuring devices. Furthermore, the water treatment management system 20 includes a calculation unit 26 that performs calculations based on the concentration of the specific organic component measured by the specific organic component measuring device 23 and the TOC concentration measured by the TOC meter 25, and a flow path control unit 27 that controls the pretreatment flow path network 40 based on the calculation results of the calculation unit 26. The calculation unit 26 and the flow path control unit 27 will be described later.

[0019] Next, the pretreatment flow network 40 will be described. The pretreatment flow network 40, located between the raw water tank 11 and the water treatment system 10, includes multiple flow paths. One of these flow paths supplies raw water directly to the water treatment system 10, while the remaining flow paths are each equipped with a pretreatment device for pretreatment of the raw water. The pretreatment flow network 40 shown in FIG. 1 is used when the specific organic component measuring device 23 is, for example, composed of a urea meter and a VOC meter. In this pretreatment flow network 40, a pipe 12 extends from the raw water tank 11. Valves 41 and 46 are installed in series on this pipe 12, with the valve 41 located upstream. A valve 61 is installed at the end of the pipe 12 for discharging raw water directly to the outside. Flow paths 42 bypass both ends of the valve 41. A VOC removal device 43 for removing volatile organic substances from the water is installed in the flow path 42 as a pretreatment device, and valves 44 and 45 are installed at the inlet and outlet of the VOC removal device 43, respectively. The VOC removal device 43 is a device that transfers volatile organic substances in raw water to the air side by bringing oxygen, nitrogen, or the like into gas-liquid contact. Alternatively, it may be a device equipped with a hollow fiber membrane that removes volatile organic substances by degassing under reduced pressure using, for example, a vacuum pump.

[0020] Similarly, a flow path 47 is provided that bypasses both ends of the valve 46. A urea removal device 48 is provided in the flow path 47 as a pretreatment device, and valves 49 and 50 are provided at the inlet and outlet of the urea removal device 48, respectively. The urea removal device 48 is a device that removes urea from water, and is a device that decomposes and removes urea using hypobromous acid, which is generated when a bromide salt and an oxidizing agent are added, for example. Alternatively, the urea decomposition device 48 may be a device that removes urea using organisms, or a device that decomposes and removes urea by ultraviolet oxidation treatment after adding an appropriate oxidizing agent.

[0021] Two flow paths 52 and 57 branch off from the pipe 12 between the outlet of the valve 46 and the valve 61, and the ends of these flow paths 52 and 57 are both connected to the pipe 13. A persistent TOC removal device 53 is provided in the flow path 52 as a pretreatment device, and valves 54 and 55 are provided at the inlet and outlet of the persistent TOC removal device 53, respectively. The persistent TOC removal device 53 is a device that removes persistent TOC components from water, and decomposes and removes persistent TOC components by, for example, combining the addition of persulfuric acid (peroxodisulfuric acid) or its salts with ultraviolet oxidation treatment. On the other hand, the flow path 57 is a flow path that bypasses the persistent TOC removal device 53 and is provided only with a valve 59.

[0022] In this pretreatment flow network 40, flow paths 42, 47, and 52, each equipped with a pretreatment device, are connected in series to a pipe 12 that supplies raw water to the water treatment system 10. By selecting one or more of flow paths 42, 47, 52, and 57 with valve 61 closed, it is possible to select whether raw water from the raw water tank 11 is directly supplied to the water treatment system 10, or whether the raw water is pretreated in one or more of the pretreatment devices, namely, the VOC removal device 43, the urea removal device 48, and the persistent TOC removal device 53, before being supplied to the water treatment system 10. However, flow paths 52 and 57 cannot be selected simultaneously. For example, by closing valve 41 and opening valves 44 and 45 to allow the raw water to flow through flow path 42, the raw water will be supplied to the water treatment system 10 via the VOC removal device 43, and volatile organic compounds in the raw water will be decomposed and removed by the VOC removal device 43 as pretreatment for, for example, ultrapure water production. In this case, the raw water from which volatile organic substances have been removed is supplied to the water treatment system 10. Similarly, if valve 46 is closed and valves 49 and 50 are opened to allow the raw water to flow through flow path 47, the raw water will be supplied to the water treatment system 10 via the urea removal device 48, and the urea in the raw water will be decomposed and removed by the urea removal device 48. In this case, too, the raw water from which urea has been removed is supplied to the water treatment system 10. However, the urea removal device 48 does not remove most of the persistent TOC components other than urea. Note that if both flow paths 42 and 47 are selected, the raw water will pass through the VOC removal device 43 and the urea removal device 48 in that order. 1, the flow paths 42, 47, and 52 are arranged in series in the following order from the upstream side in the flow direction of the raw water: flow path 42 equipped with a VOC removal device 43, flow path 47 equipped with a urea removal device 48, and flow path 52 equipped with a persistent TOC removal device 53. However, the arrangement order of the flow paths 42, 47, and 52 is not limited to this. Furthermore, appropriate piping and valves may be provided so that the order in which raw water flows through the three flow paths 42, 47, and 52 can be changed, and the order in which water flows through these flow paths 42, 47, and 52 may be controlled based on the measured quality of the raw water.For example, the order in which water is passed through the VOC removal device 43 and the urea removal device 48 is not limited to this, and the flow path configuration in the pretreatment flow path network 40 may be changed so that the water passes through the urea removal device 48 before passing through the VOC removal device 43. When raw water is passed through multiple pretreatment devices including the persistent TOC removal device 53 in the pretreatment flow path network 40, it is preferable to pass the raw water through the persistent TOC removal device 53 last, from the standpoint of reducing operating costs, etc.

[0023] When valve 59 is closed and valves 54 and 55 are opened to allow raw water to flow through flow path 52, the raw water is supplied to water treatment system 10 via persistent TOC removal device 53, and persistent TOC components in the raw water are decomposed and removed by persistent TOC removal device 53 as pretreatment for producing ultrapure water, etc. In this case, the raw water from which the persistent TOC components have been removed is supplied to water treatment system 10. Conversely, when valves 54 and 55 are closed and valve 59 is opened to allow raw water to flow through flow path 57, the raw water is supplied to water treatment system 10 without passing through persistent TOC removal device 53.

[0024] 1, the configuration of the pretreatment flow network 40 for measuring the urea concentration and the volatile organic substance concentration in the specific organic component measuring device 23 has been described. In a water treatment management system including such a pretreatment flow network 40, if the concentration of persistent TOC components contained in the raw water is below a predetermined level, the raw water in the raw water tank 11 is supplied directly to the water treatment system 10 without pretreatment in the pretreatment flow network 40. If the concentration of persistent TOC components or specific organic components contained in the raw water exceeds a predetermined level, the pretreatment flow network 40 performs pretreatment using at least one of the VOC removal device 43, the urea removal device 48, and the persistent TOC removal device 53 before supplying the raw water to the water treatment system 10. The calculation unit 26 and the flow path control unit 27 are provided in the water treatment management device 20 to perform such control. The calculation unit 26 performs calculations based on the concentration of the specific organic component measured by the specific organic component measuring device 23 and the TOC concentration measured by the TOC meter 26. Based on the calculation results obtained by the calculation unit 26, the flow path control unit 27 controls the valves 41, 44-46, 49, 50, 54, 55, 59, and 61 of the pretreatment flow path network 40 to select a flow path, thereby controlling the supply of raw water to the water treatment system 10 via one or more of the VOC removal device 43, the urea removal device 48, and the persistent TOC removal device 53, or without passing through such one or more. That is, the flow path control unit 27 controls the flow path of the raw water to the water treatment system 10 based on the calculation results obtained by the calculation unit 26. At this time, the operating conditions of each of the pretreatment devices, the VOC removal device 43, the urea removal device 48, and the persistent TOC removal device 53, may be controlled based on the calculation results obtained by the calculation unit 26. For example, the amount of air blown by a blower or the degree of vacuum of a vacuum pump may be controlled for the VOC removal device 43; the amount of chemicals added may be controlled for the urea removal device 48; and the amount of chemicals added or the amount of ultraviolet light irradiation may be controlled for the persistent TOC removal device 53.

[0025] A specific example of control is explained below. The TOC concentration measured by a TOC meter is TOC The concentration of volatile organic substances measured by the VOC meter of the specific organic component measuring device 23 is C VOC The urea concentration measured by the urea meter of the specific organic component measuring device 23 is CU To achieve this control, several thresholds are set. The threshold for TOC concentration is set as T TOC and the threshold value for the concentration of volatile organic substances is T VOC The threshold for urea concentration is T U The threshold value for the ratio of volatile organic substance concentration to TOC concentration is T A The threshold value for the ratio of urea concentration to TOC concentration is T B Then, based on the relationship between the measured concentration and each threshold value, the calculation unit 26 and the flow path control unit 27 perform control based on case distinction as shown below.

[0026] (1) Under normal conditions, when the concentration of persistent TOC components is low, i.e., T TOC >C TOC When this is the case, the valves 44, 45, 49, 50, 54, 55, and 61 are closed, and the valves 41, 46, and 59 are opened so that the raw water is supplied directly from the pipe 12 to the flow path 57 and is supplied directly to the water treatment system 10.

[0027] (2) When the concentration of volatile organic substances is high, i.e., T TOC ≦C TOC , T VOC ≦C VOC , T U >C U , C VOC / C TOC ≧T A If all of the above conditions are met, valves 41, 49, 50, 54, 55, and 61 are closed, and valves 44 to 46 and 59 are opened so that raw water is supplied from pipe 12 to flow path 42, passes through VOC removal device 43, and is then supplied to water treatment system 10.

[0028] (3) When the urea concentration is high, i.e., T TOC ≦C TOC , T VOC >C VOC , T U ≦C U , C U / C TOC ≧T BIf all of the above conditions are met, valves 44 to 46, 54, 55, and 61 are closed, and valves 41, 49, 50, and 59 are opened so that raw water is supplied from pipe 12 to flow path 47, passed through urea removal device 48, and then supplied to water treatment system 10.

[0029] (4) When both the volatile organic substance concentration and the urea concentration are high, i.e., T TOC ≦C TOC , T VOC ≦C VOC , T U ≦C U , C VOC / C TOC ≧T A , C U / C TOC ≧T B If all of the above conditions are met, the valves are controlled in the same way so that the raw water passes through the VOC removal device 43 and the urea removal device 48 in that order, and then is supplied to the water treatment system 10.

[0030] (5) When TOC components other than volatile organic compounds or urea are high, they are further subdivided into several cases. TOC ≦C TOC , T VOC >C VOC , T U >C U If all of the above conditions are met, the valves are controlled in the same way so that the raw water is supplied to the flow path 52, passes through the persistent TOC removal device 53, and is then supplied to the water treatment system 10. TOC ≦C TOC , T VOC ≦C VOC , T U ≦C U , C VOC / C TOC <T A , C U / C TOC <T B If all of the above conditions are met, the valves are controlled in the same way so that the raw water passes through the VOC removal device 43, the urea removal device 48, and the persistent TOC removal device 53 in that order, and then is supplied to the water treatment system 10.

[0031] The persistent TOC removal device 53 can decompose and remove both volatile organic compounds (VOCs) and urea, but its operating costs are higher than those of the VOC removal device 43 and the urea removal device 48. Therefore, in the control example shown above, raw water is pretreated as much as possible in the VOC removal device 43 and the urea removal device 48, with the aim of reducing operating costs. Therefore, depending on the tradeoffs, etc., it is possible to pretreat raw water using only the persistent TOC removal device 53, or to pretreat raw water by combining the persistent TOC removal device 53 with the VOC removal device 43 or the urea removal device 48, without being bound by the above control example. Furthermore, the above control example is merely an example, and flow paths in the pretreatment flow network 40 can be selected based on other algorithms. For example, when the urea concentration is high, the presence or absence of other TOC components can be determined from the difference between the TOC concentration measured by a TOC meter and the urea concentration, and the flow paths in the pretreatment flow network 40 and the operating conditions of each removal device can be controlled based on the determination results.

[0032] In the present invention, the pretreatment devices provided in the pretreatment flow network 40 are not limited to the VOC removal device 43, the urea removal device 48, and the persistent TOC removal device 53, but are selected according to the measurement items in the water treatment management system 20. In other words, when the concentration of a specific organic component is measured by the specific organic component measuring device 23, a removal device for removing the specific organic component is provided in one of the flow paths of the pretreatment flow network 40 to perform treatment to remove the specific organic component from the raw water. For example, when the specific organic component measuring device 23 is equipped with a trihalomethane meter, the pretreatment flow network 40 is provided with a trihalomethane removal device as a pretreatment device.

[0033] FIG. 2 is a flowchart specifically illustrating flow path control in this embodiment. Here, it is assumed that the specific organic component measuring device 23 in the water treatment management system shown in FIG. 1 is composed only of a urea meter, and that the pretreatment flow path network 40 does not include the valves 41, 44, and 45, the flow path 42, and the VOC removal device 43. Therefore, three thresholds are used for control: a first threshold Th1 related to the TOC concentration, a second threshold Th2 related to the urea concentration, and a third threshold Th3 related to the ratio of the urea concentration to the TOC concentration. First, in step 101, the calculation unit 26 determines whether the TOC concentration measured by the TOC meter 25 is equal to or greater than the first threshold Th1. If the TOC concentration measured by the TOC meter 25 is equal to or greater than the first threshold Th1, this indicates that the target water, which is raw water, contains persistent TOC components at a certain level or higher. Therefore, if the TOC concentration is less than the first threshold value Th1 in step 101, the flow path control unit 27 opens the valves 46 and 59 in the pretreatment flow path network 40 and closes the remaining valves 49, 50, 54, 55, and 61 in step 102, so that the raw water is supplied directly from the pipe 12 to the water treatment system 10 via the flow path 57. If the TOC concentration is equal to or greater than the first threshold value Th1 in step 101, the calculation unit 26 then determines whether the urea concentration is equal to or greater than the second threshold value Th2 in step 103. If the urea concentration is less than the second threshold value Th2, the raw water contains persistent TOC components but is not urea. Therefore, in step 104, the flow path control unit 27 opens the valves 46, 54, and 55 in the pretreatment flow path network 40 and closes the remaining valves 49, 50, 59, and 61, so that the raw water is treated in the persistent TOC removal device 53 via the flow path 52 and then supplied to the water treatment system 10.

[0034] If the urea concentration is equal to or greater than the second threshold value Th2 in step 103, the calculation unit 26 determines whether (urea concentration / TOC concentration) is equal to or greater than the third threshold value Th3 in step 105. If (urea concentration / TOC concentration) is equal to or greater than the third threshold value Th3, this means that urea accounts for a significant portion of the persistent TOC components contained in the raw water. Therefore, in step 106, the flow path control unit 27 opens the valves 49, 50, and 59 in the pretreatment flow path network 40 and closes the remaining valves 46, 54, 55, and 61 so that the raw water is treated in the urea removal device 48 via the flow path 47 and then supplied to the water treatment system 10 via the flow path 57. On the other hand, if (urea concentration / TOC concentration) is less than the third threshold value Th3 in step 105, it means that persistent TOC components other than urea cannot be ignored, so the process of step 104 is executed, and the flow path control unit 27 causes the raw water to be treated in the persistent TOC removal device 53 via the flow path 57 before being supplied to the water treatment system 10. In order to respond to the ever-changing water quality of the raw water, after the flow path selection has been performed in steps 102, 104, and 106, the process from step 101 is repeated.

[0035] In the control flow shown in FIG. 2, when the TOC concentration is equal to or greater than the first threshold value Th1, raw water is pretreated by the urea removal device 48 or the persistent TOC removal device 53. The selection of whether to use either the urea removal device 48 or the persistent TOC removal device 53, or both, for raw water pretreatment is not limited to that described with reference to FIG. 2. For example, in the procedure shown in FIG. 2, the determination process of step 105 may be omitted, and raw water may always be pretreated by the urea removal device 48 when the urea concentration is equal to or greater than the second threshold value Th2 in step 103. The first to third threshold values ​​Th1 to Th3 in the procedure shown in FIG. 2, which are based on the TOC concentration and the urea concentration, are determined as appropriate depending on the configuration and application of the water treatment system 10. For example, the first threshold value Th1 is set between 0.5 and 5 ppb, preferably between 0.5 and 3 ppb, and more preferably between 0.5 and 1 ppb. The second threshold value Th2 is set, for example, between 0.1 and 2 ppb, preferably between 0.1 and 1 ppb, and more preferably between 0.1 and 0.3 ppb, in terms of carbon. The third threshold value Th3 is set, for example, between 0.2 and 0.4.

[0036] According to the process of the present embodiment described above, when persistent TOC components are contained in raw water to be supplied to the water treatment system 10, pretreatment is performed to remove the persistent TOC components, regardless of whether the persistent TOC components are urea. Therefore, when the water treatment system 10 is an ultrapure water production system, for example, deterioration in the quality of the resulting ultrapure water can be prevented. When the raw water contains organic components other than persistent TOC components that may affect the treated water quality of the water treatment system 10, pretreatment is performed to remove the organic components before supplying the raw water to the water treatment system 10. This similarly prevents deterioration in the water quality at the outlet of the water treatment system 10. Furthermore, while the persistent TOC removal device 53 using persulfuric acid, for example, has significantly higher operating costs than the VOC removal device 43 or the urea removal device 48, according to the present embodiment, when the persistent TOC components contained in the raw water are mainly urea or when the raw water contains volatile organic substances, pretreatment of the raw water is performed in the VOC removal device 43 or the urea removal device 48. This reduces the operating costs of the entire water treatment management system.

[0037] [Second embodiment] The water treatment control system according to the present invention is not limited to the one shown in FIG. 1. FIG. 3 is a diagram illustrating a water treatment control system according to a second embodiment, showing the configuration of a water treatment control device 20 provided in the water treatment control system. In the water treatment control system of the second embodiment, the same pretreatment flow path network 40 as that used in the first embodiment is used. The water treatment control device 20 shown in FIG. 3 is the same as the water treatment control device 20 shown in FIG. 1, except that the position of the specific organic component measuring device 23 is changed so that a portion of the outlet water of the evaluation pure water production section 30 is supplied to the specific organic component measuring device 23 via a valve 22. Urea is also a persistent TOC component, but some of it may be removed in the evaluation pure water production section 30. Therefore, by measuring the urea concentration in the outlet water of the evaluation pure water production section 30 as shown in FIG. 3, more accurate flow path control in the pretreatment flow path network 40 is possible. For specific organic components other than urea, by measuring their concentrations in the outlet water of the evaluation pure water production unit 30 as shown in Figure 3, it becomes possible to more accurately control the flow paths in the pretreatment flow path network 40.

[0038] [Third embodiment] The concentration of a specific organic component or the TOC concentration can be measured at multiple locations in the evaluation pure water production unit 30, rather than at a single location. Figure 4 is a diagram illustrating a water treatment management system according to a third embodiment, showing the configuration of a water treatment management device 20 provided in the water treatment management system. In the water treatment management system according to the third embodiment, the same pretreatment flow path network 40 as that used in the first embodiment is used.

[0039] The water treatment management system 20 shown in Fig. 4 is the same as the water treatment management system 20 shown in Fig. 3, except that a portion of the raw water supplied as target water to the evaluation pure water production unit 30 is supplied to the specific organic component measuring device 23 via valve 22a and then to the TOC meter 25 via valve 24a, and a portion of the permeated water (RO permeated water) from the reverse osmosis membrane device 32 is supplied to the specific organic component measuring device 23 via valve 22b and then to the TOC meter 25 via valve 24b. Furthermore, the water treatment management system 20 of the third embodiment is provided with a valve 37 for discharging the raw water supplied as target water to the outside. By controlling the opening and closing of valves 22, 22a, and 22b, the specific organic component measuring device 23 can switch between the target water, the RO permeated water, and the outlet water of the evaluation pure water production unit 30 and measure the concentrations of specific organic components contained in these waters. Similarly, by controlling the opening and closing of valves 24, 24a, and 24b, TOC meter 25 can switch between measuring the TOC concentration of the target water, the TOC concentration of the RO permeate water, and the TOC concentration of the outlet water of the evaluation pure water production unit 30. By being able to measure the concentrations of specific organic components and TOC concentrations at multiple measurement points in this way, it is possible to determine, for example, the TOC removal rate in the sample pure water production unit 30 from the TOC concentration of the target water and the outlet water of the evaluation pure water production unit 30. In this embodiment, if the TOC removal rate is high even when the TOC concentration of the target water is high, flow path control can be performed, such as supplying raw water to the water treatment system 10 via the pretreatment flow network 40 as in the above-mentioned embodiment, and discharging the raw water to the outside via valve 57 of the pretreatment flow network 40 when the TOC removal rate is low. [Example]

[0040] The present invention will now be described in more detail with reference to examples and comparative examples. The examples and comparative examples described below are merely illustrative and do not limit the present invention.

[0041] [Example 1] The water treatment control system shown in Figure 1 was assembled. An ultrapure water production system was used as the water treatment system 10. In the water treatment control system 20, a reverse osmosis membrane device 32 with a membrane area of ​​3.5 m 2The UV irradiation device 33 used was a low-pressure UV oxidation device manufactured by PhotoScience Co., Ltd., with an irradiation dose of 0.4 kWh / m. 3 The cartridge polisher 34 was an ESP-2 manufactured by Organo Corporation, and the water flow rate was 60 (L / LR) / h. The specific organic component measuring device 23 was a urea meter (an online urea concentration meter ORUREA (registered trademark) manufactured by Organo Corporation) that measures urea concentration. The TOC meter 25 was an online TOC concentration meter 500RLe manufactured by Sievers. As pretreatment equipment, a device having a urea removal device 48 and a persistent TOC removal device 53 was used as the pretreatment flow network 40. The pretreatment flow network 40 was not provided with a VOC removal device 43. The urea concentration measured by the specific organic component measuring device 23, which is a urea meter, was taken as the urea concentration in the inlet water of the water treatment management device 20, and the TOC concentration measured by the TOC meter 25 was taken as the TOC concentration in the inlet water of the water treatment management device 20. To perform the control described with reference to FIG. 2, the threshold values ​​used in the flow path control unit 27 were set as follows: the first threshold Th1 was 1 ppb, the second threshold Th2 was 0.6 ppb, and the third threshold Th3 was 0.4.

[0042] When simulated raw water was supplied to the water treatment management device 20 and the pretreatment flow network 40 as raw water, the urea concentration at the inlet water of the water treatment management device 20 was 8 ppb, which was above the second threshold value Th2, and the TOC concentration at the outlet water of the water treatment management device 20 was 10 ppb, which was above the first threshold value Th1. Since the (urea concentration / TOC concentration) ratio was 0.8, which was above the third threshold value Th3, it was determined that the persistent TOC component contained in the simulated raw water was urea. The flow path control unit 27 controlled the opening and closing of each valve so that the simulated raw water was supplied to the water treatment system 10 via the urea removal device 48. The urea concentration and TOC concentration in the treated water (outlet water) of the water treatment system 10 were then measured. The results are shown in Table 1.

[0043] [Example 2] The same water treatment control system and water treatment system 10 as in Example 1 were used, and simulated raw water different from that in Example 1 was supplied to the water treatment control system 20 and pretreatment flow network 40. The urea concentration in the inlet water of the water treatment control system 20 was less than 0.5 ppb, which is less than the second threshold value Th2, and the TOC concentration in the outlet water of the water treatment control system 20 was 10 ppb, which is greater than the first threshold value Th1. Therefore, the persistent TOC components contained in the simulated raw water were determined to be organic components other than urea. The ratio (urea concentration / TOC concentration) was also less than 0.05, which is less than the third threshold value Th3. The flow path control unit 27 controlled the opening and closing of each valve so that the simulated raw water was supplied to the water treatment system 10 via the persistent TOC removal device 43. The urea concentration and TOC concentration in the treated water (outlet water) of the water treatment system 10 were measured. The results are shown in Table 1.

[0044] [Comparative Example 1] A system with the same configuration as in Example 2 was used, except that the specific organic component measuring device 23, which is a urea meter, was removed from the water treatment management device 20 of the water treatment management system used in Example 2. Since the urea concentration was not measured in Comparative Example 1, when a persistent TOC component was detected, it was assumed to be urea, and control was performed so that raw water pretreated by the urea removal device 48 in the pretreatment flow network 40 was supplied to the water treatment system 10. The same simulated raw water as used in Example 2 was supplied to the water treatment management device 20 and the pretreatment flow network 40. The TOC concentration in the outlet water of the water treatment management device 20 was 10 ppb, and it was determined that the simulated raw water contained persistent TOC components. The flow path control unit 27 then controlled the opening and closing of each valve so that the simulated raw water was supplied to the water treatment system 10 via the urea removal device 48. The urea concentration and TOC concentration in the treated water (outlet water) of the water treatment system 10 were measured. The results are shown in Table 1.

[0045] [Table 1]

[0046] As can be seen from the results shown in Table 1, in Example 1, the TOC concentration in the outlet water of the water treatment management device 20 was equal to or greater than the first threshold value Th1, the urea concentration in the inlet water of the water treatment management device 20 was equal to or greater than the second threshold value Th2, and (urea concentration / TOC concentration) was equal to or greater than the third threshold value Th3, so it was possible to determine that the persistent TOC component contained in the simulated raw water was urea. Therefore, by treating the simulated raw water with the urea removal device 48 before supplying it to the water treatment system 10, it was possible to supply raw water that does not contain persistent TOC components to the water treatment system 10, and it was possible to maintain the quality of the outlet water of the water treatment system 10, i.e., the treated water.

[0047] Similarly, in Example 2, the TOC concentration in the outlet water of the water treatment management device 20 was equal to or higher than the first threshold value Th1, and the urea concentration in the inlet water of the water treatment management device 20 was less than the second threshold value Th2, so it was possible to determine that the persistent TOC components contained in the simulated raw water were persistent TOC components other than urea. Therefore, by treating the simulated raw water with the persistent TOC removal device 53 before supplying it to the water treatment system 10, it was possible to supply raw water that did not contain persistent TOC components to the water treatment system 10, and the quality of the treated water from the water treatment system 10 was able to be maintained.

[0048] The simulated raw water used in Comparative Example 1 was the same as that used in Example 2, and therefore contained persistent TOC components other than urea. However, in Comparative Example 1, the urea concentration of the simulated raw water was not measured. Instead, it was determined that the simulated raw water contained urea when the TOC concentration in the outlet water of the water treatment management device 20 was equal to or higher than, for example, a first threshold value Th1. Based on this determination, the simulated raw water was treated in the urea removal device 48 before being supplied to the water treatment system 10. As a result, in Comparative Example 1, raw water containing persistent TOC components other than urea was supplied to the water treatment system 10, and the quality of the treated water from the water treatment system 10 deteriorated, as shown in Table 1.

[0049] As is clear from the above-described Examples and Comparative Examples, according to the present invention, when it is determined that raw water to be supplied to a water treatment system contains persistent TOC components, it is possible to evaluate, for example, whether the persistent TOC components are urea or other organic components, and to perform appropriate pretreatment of the raw water depending on the evaluation results, thereby enabling appropriate operation management of the water treatment system and, in particular, enabling the water treatment system to operate stably regardless of the quality of the raw water.Furthermore, when it is determined that the persistent TOC component is urea, the urea can be removed using a urea removal device, thereby reducing the operating costs required for removing the persistent TOC components. [Explanation of symbols]

[0050] 10 Water Treatment Systems 11 Raw water tank 20 Water Treatment Management Unit 23 Specific organic component measuring device 25 TOC total 26 Arithmetic section 27 Supply water production department 30 Evaluation Purified Water Production Department 31 Heat exchanger (HE) 32 Reverse osmosis membrane device (RO) 33 Ultraviolet oxidation equipment (UV) 34 Cartridge Polisher (CP) 40 Pretreatment flow network 43 VOC removal equipment 48 Urea removal equipment 48 Persistent TOC removal equipment

Claims

1. A water treatment management device used for operation management of a water treatment system, a pure water production unit for evaluation, which is equipped with a TOC removal device that performs a unit operation to remove TOC components, and through which raw water to be supplied to the water treatment system is passed as target water; a TOC measuring device that measures a TOC concentration in at least the outlet water of the evaluation pure water producing unit as a first concentration value; a specific organic component measuring device that measures a concentration of a specific organic component, which is different from the TOC concentration, in the water flowing through the evaluation pure water producing unit as a second concentration value; a calculation unit that performs calculation based on the first density value and the second density value; a flow path control unit that controls a flow path for supplying the raw water to the water treatment system based on a result of the calculation by the calculation unit; A water treatment management device having the above structure.

2. 2. The water treatment management system according to claim 1, wherein the specific organic component measuring device measures the concentration of the specific organic component in at least the outlet water of the evaluation pure water producing section.

3. The water treatment management device according to claim 1 or 2, wherein the calculation unit calculates a division value by dividing the second concentration value by the first concentration value, and the flow path control unit controls the flow path in accordance with the division value.

4. 4. The water treatment management device according to claim 1, wherein a plurality of measurement points are set in the evaluation pure water production section, including an inlet and an outlet of the evaluation pure water production section, the TOC measurement device measures the TOC concentration at the plurality of measurement points, and the specific organic component measurement device measures the concentration of the specific organic component at the plurality of measurement points.

5. The water treatment management device according to any one of claims 1 to 4, a pretreatment flow path network including a plurality of flow paths arranged in series with each other in a path for supplying the raw water to the water treatment system; The water treatment management system is configured to control a flow path for supplying the raw water to the water treatment system by selecting one or more flow paths from the pretreatment flow path network.

6. The water treatment management system according to claim 5 , wherein pretreatment devices for pretreating raw water are provided in at least one flow path of the pretreatment flow path network.

7. The water treatment management system according to claim 6 , wherein the pretreatment equipment comprises a removal device that removes the specific organic components from the raw water.

8. The water treatment management system according to claim 6 or 7, wherein a persistent TOC removal device is provided as the pretreatment device.

9. A water treatment method for supplying raw water to a water treatment system, comprising: a step of passing the raw water as test water through a pure water production unit for evaluation, which is provided separately from the water treatment system and has a TOC removal device that performs a unit operation of removing TOC components; a first measuring step of measuring a TOC concentration in at least the outlet water of the evaluation pure water producing unit as a first concentration value; a second measuring step of measuring a concentration of a specific organic component, which is different from the TOC concentration, in the water flowing through the evaluation pure water producing unit as a second concentration value; a flow path control step of controlling a flow path for supplying the raw water to the water treatment system based on a result of calculation based on the first concentration value and the second concentration value; A water treatment method comprising the steps of:

10. The water treatment method according to claim 9, wherein the flow path control step is a step of selecting one flow path from one or more flow paths that perform pretreatment on the raw water and a flow path that supplies the raw water directly to the water treatment system.

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